Formation of nucleoli in a cell-free system
Project management at the University of Würzburg:
Due to a large stockpile of ribosomes stored in the egg, the protein synthesis of preblastula Xenopus embryos is based entirely on ribosomes of maternal origin. Only after the midblastula transition, when the embryonic genome is being activated, typical nucleoli emerge by a stepwise process which, however, is poorly understood. The early Xenopus development therefore represents an interesting model system to analyze mechanisms involved in rDNA gene activation and nucleolar assembly. Transcription of the rRNA genes requires RNA polymerase I and several basal transcription factors including UBF and the multiprotein complex TBP. To gain insight into the mechanisms causing transcriptional quiescence of the rRNA genes and nucleolar absence at preblastula stages, we have studied the expression and localization of the pol I transcription machinery in embryos and "synthetic" nuclei assembled from sperm chromatin.
Projekt period: from 01.1995 to 11.1997
DFG ( Sche 157/10-1 ) ,Granting date: 23.08.1994